/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.sdk.io.kudu;



import com.bff.gaia.unified.sdk.io.BoundedSource;

import org.apache.kudu.client.KuduException;



import java.io.Serializable;

import java.util.List;



/** An interface for real, mock, or fake implementations of Kudu services. */

interface KuduService<T> extends Serializable {



  /**

   * Returns a {@link BoundedSource.BoundedReader} that will read from Kudu

   * using the spec from {@link KuduIO.KuduSource}.

   */

  BoundedSource.BoundedReader<T> createReader(KuduIO.KuduSource<T> source);



  /** Create a {@link Writer} that writes entities into the KKudu instance. */

  Writer createWriter(KuduIO.Write<T> spec) throws KuduException;



  /** Returns a list containing a serialized scanner per tablet. */

  List<byte[]> createTabletScanners(KuduIO.Read<T> spec) throws KuduException;



  /** Writer for an entity. */

  interface Writer<T> extends AutoCloseable, Serializable {



    /**

     * Opens a new session for writing. This must be called exactly once before calling {@link

     * #write(Object)}.

     */

    void openSession() throws KuduException;



    /**

     * Writes the entity to Kudu. A call to {@link #openSession()} must be made before writing.

     * Writes may be asynchronous in which case implementations must surface errors when the session

     * is closed.

     */

    void write(T entity) throws KuduException;



    /** Closes the session, surfacing any errors that may have occurred during writing. */

    void closeSession() throws Exception;

  }

}